General introduction General introduction to to

EntomologyEntomology

Entomology

“Entomology is the study of insects” Entoma; Mean segmented/Engrave. Logos; Mean study Both are Greek words What are insects Insects are Arthropods examples are;- Beetles, lice, bugs, fleas, mosquitoes, honey

bees, butterflies, flies, wasps, grasshoppers, spiders, ticks, scorpion, mites, lobsters, millipedes, shrimps etc.

Insects are in the phylum Arthropoda Arthropoda

(“jointed leg”)(“jointed leg”) The phylum is divided into 6 smaller groups called classes:

Crustacea (e.g. crabs, lobsters, shrimps) Chilopoda (e.g.centipedes) Diplopoda (e.g.millipedes) Arachnida (spiders,ticks, mites,scorpion)

Insecta insects (flies, lice, fleas, bugs)

All arthropods have following characteristics:

1) Arthropods have a segmented body

2) All arthropods have paired, jointed legs

3) All arthropods have a chitinous exoskeleton (which is periodically shed and renewed as the animal grows)

4) All arthropods have a digestive system (tube that runs from head to tail)

5) All arthropods have an “open” circulatory system, no veins, arteries etc. Blood is held in a dorsal tubular structure with lateral openings in the abdomen.

6) All arthropods have a ventral nervous system which consists of a tiny brain, paired nerve cords which extend from the brain backward, and nerve centers called ganglia.

7) All arthropods breathe by means of gills, or tracheae and spiracles.

8) Separate sexes (nearly always)

The Class Crustacea (lobster, shrimp, crab) have two pairs of antennae and at least five pairs of legs.

The classes Chilopoda and Diplopoda.(centipedes, millipedes.) have antennae,many legs and only two body regions.They add segments as they molt.

The class Arachnida have 8 legs and no antennae.

Classification Of EntomologyKingdom: Animalia

Phylum: Arthropoda

Class: Insecta

(Class: Arachnida)

More than 1 million species of More than 1 million species of insects world-wideinsects world-wide

Relation of insects to humans:Relation of insects to humans:

1.Beneficial: Pollination, break down raw materials, food for many animals.2. Injurious: Feed on plants, stored foods, woods, fabrics, humans, and animals

The InsectsThe Insects

1. Three, usually distinct body regions (head, thorax, and abdomen)

2. One pair of segmented antennae

3. Usually have one pair of compound eyes

4. Three pairs of legs

5. Two pair of wings usually (some have only one pair (i.e., flies) or no wings at all).

The Head. Functions mainly for feeding and sensory perception.

The Thorax. Responsible for locomotion. Made up of 3 segments. A pair of legs arise from each segment. Wings, if present, arise from2nd and 3rd segment.

The Abdomen is responsible for excretion and reproduction.

Growth and DevelomentMetamorphosis - The process of change from egg to adult.Incomplete or gradual metamorphosis. Baby insects (nymphs) look similar to adults (Bugs, grasshoppers, aphids, cockroaches). Growth occurs through molting.

Complete metamorphosis. Larvae look nothing like adults. The larvae pass through a pupal stage to change into the adult form (wasps, beetles, moths, butterflies, flies).

How Insects FeedHow Insects Feed

Insects can be separated by the typeInsects can be separated by the typeof mouthparts they possess which of mouthparts they possess which dictates the type of job they have.dictates the type of job they have.

Most common typeMost common typeof mouthpart isof mouthpart ischewingchewing..

Tear off pieces ofTear off pieces oftissue and eat it.tissue and eat it.

Plant damage caused by Plant damage caused by pests with chewing mouthpartspests with chewing mouthparts